Dumbbell



FIG. 1 is a perspective view of a dumbbell showing my new design;

FIG. 2 is a front/rear elevational view thereof;

FIG. 3 is a left/right side elevational view thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof.

Left and right portions of the dumbbell are symmetrical, and front and rear portions of the dumbbell are symmetrical.

The evenly-dashed broken lines depict portions of a dumbbell in which the design is embodied that form no part of the claimed design.

The dash-dotted broken lines are for defining the bounds of the claimed design only and form no part of the claimed design. 

CLAIM The ornamental design for a dumbbell, as shown and described. 